On Positivity Preserving, Translation Invariant, Operators in $L^p({\mathbb{R}}^n{)}^m$

Fritz Gesztesy, Michael M. H. Pang

We characterize positivity preserving, translation invariant, linear operators in $L^p({\mathbb{R}}^n{)}^m$, $p\in [1,\infty )$, $m,n\in \mathbb{N}$.